So the only thing you would need to do would be to have rules that anyplace with more than say 6 registered voters from the same address would require signature verification.

As long as we have a system without common sense QA processes all systems are easy to violate.

Again, I see these ballots as easier to protect as any, further I personally would support that absentee ballots nor be picked up but rather mailed with a random mailing pattern

I think absentee ballots are quite valuable, and again not hard to protect to a degree that makes massive corruption possible without a huge investment of effort

Our absentee ballots (from a county election office in the state of Washington) go in a plain envelope which goes in a second envelope. The signature goes on the second envelope.

Why couldn't the signature go across the sealing flap of the second envelope - so that part is on the flap and part is not? Then if the envelope is signed before it is sealed, it would very-often (not always) be fairly apparent.